Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935795AbZAPCBq (ORCPT ); Thu, 15 Jan 2009 21:01:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S935227AbZAPCBC (ORCPT ); Thu, 15 Jan 2009 21:01:02 -0500 Received: from TYO202.gate.nec.co.jp ([202.32.8.206]:64854 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935869AbZAPCAv (ORCPT ); Thu, 15 Jan 2009 21:00:51 -0500 Date: Fri, 16 Jan 2009 10:50:09 +0900 From: Daisuke Nishimura To: "Andrew Morton" Cc: KAMEZAWA Hiroyuki , "LKML" , "linux-mm" , "Balbir Singh" , "Pavel Emelyanov" , "Li Zefan" , "Paul Menage" , nishimura@mxp.nes.nec.co.jp Subject: [BUGFIX][PATCH] memcg: get/put parents at create/free Message-Id: <20090116105009.7cabac46.nishimura@mxp.nes.nec.co.jp> In-Reply-To: <20090115181056.74a938d5.kamezawa.hiroyu@jp.fujitsu.com> References: <20090113184533.6ffd2af9.nishimura@mxp.nes.nec.co.jp> <20090114175121.275ecd59.nishimura@mxp.nes.nec.co.jp> <7602a77a9fc6b1e8757468048fde749a.squirrel@webmail-b.css.fujitsu.com> <20090115100330.37d89d3d.nishimura@mxp.nes.nec.co.jp> <20090115110044.3a863af8.kamezawa.hiroyu@jp.fujitsu.com> <20090115111420.8559bdb3.nishimura@mxp.nes.nec.co.jp> <20090115133814.a52460fa.nishimura@mxp.nes.nec.co.jp> <20090115164537.d402e95f.nishimura@mxp.nes.nec.co.jp> <20090115165453.271848d9.kamezawa.hiroyu@jp.fujitsu.com> <20090115171315.965da4e3.nishimura@mxp.nes.nec.co.jp> <20090115172336.0ed780bb.kamezawa.hiroyu@jp.fujitsu.com> <20090115175131.9542ae59.nishimura@mxp.nes.nec.co.jp> <20090115181056.74a938d5.kamezawa.hiroyu@jp.fujitsu.com> Organization: NEC Soft, Ltd. X-Mailer: Sylpheed 2.4.8 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2603 Lines: 80 This version works well in my test. Andrew, please pick up this one. === From: Daisuke Nishimura The lifetime of struct cgroup and struct mem_cgroup is different and mem_cgroup has its own reference count for handling references from swap_cgroup. This causes strange problem that the parent mem_cgroup dies while child mem_cgroup alive, and this problem causes a bug in case of use_hierarchy==1 because res_counter_uncharge climbs up the tree. This patch is for avoiding it by getting the parent at create, and putting it at freeing. Signed-off-by: Daisuke Nishimura Reviewed-by; KAMEZAWA Hiroyuki --- mm/memcontrol.c | 23 ++++++++++++++++++++++- 1 files changed, 22 insertions(+), 1 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index fb62b43..45e1b51 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -202,6 +202,8 @@ pcg_default_flags[NR_CHARGE_TYPE] = { static void mem_cgroup_get(struct mem_cgroup *mem); static void mem_cgroup_put(struct mem_cgroup *mem); +static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem); +static void mem_cgroup_get_parent(struct mem_cgroup *mem); static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, struct page_cgroup *pc, @@ -2185,10 +2187,28 @@ static void mem_cgroup_get(struct mem_cgroup *mem) static void mem_cgroup_put(struct mem_cgroup *mem) { - if (atomic_dec_and_test(&mem->refcnt)) + if (atomic_dec_and_test(&mem->refcnt)) { + struct mem_cgroup *parent = parent_mem_cgroup(mem); __mem_cgroup_free(mem); + if (parent) + mem_cgroup_put(parent); + } +} + +static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem) +{ + if (!mem->res.parent) + return NULL; + return mem_cgroup_from_res_counter(mem->res.parent, res); } +static void mem_cgroup_get_parent(struct mem_cgroup *mem) +{ + struct mem_cgroup *parent = parent_mem_cgroup(mem); + + if (parent) + mem_cgroup_get(parent); +} #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP static void __init enable_swap_cgroup(void) @@ -2237,6 +2257,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) if (parent) mem->swappiness = get_swappiness(parent); atomic_set(&mem->refcnt, 1); + mem_cgroup_get_parent(mem); return &mem->css; free_out: __mem_cgroup_free(mem); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/